The use and application of small, autonomous, unmanned aerial vehicles (UAVs) has increased dramatically in the past few years due to an increased need for low-cost surveillance in high-risk areas. UAVs have been found to be useful in border security, battlefield surveillance, emergency response, and other similar applications. UAVs are capable of fully autonomous flight, except during landing, when manual piloting is required. Because these aircraft are flying near the lower limit of their performance envelope during landing maneuvers, this is when most UAV accidents occur. Automated landing devices which would tend to reduce UAV accidents during landings have traditionally required heavy and bulky on-board systems and mechanisms. One possible alternative to a traditional on-board automated landing system for UAVs is a ground-based system that consists of an on-board range finder that communicates with a ground-based device near the landing zone. The range finder in such an arrangement is mounted on the UAV by means of a gimbal and is directed toward the ground-based device. Alternatively, the gimbal-mounted range founder can be mounted on the ground and scan the sky for the UAV. The position of the UAV would then be determined from the gimbal orientation angles and other data generated by the range finder. This data could then provide the type of highly accurate position information required for autonomous landings of a UAV.
While such a system has been seriously considered by UAV designers, it has not been developed because of rather serious shortcomings in the art relative to a gimbal which could perform in the manner necessary to make this system operational. A principal reason that this ground based system has been, heretofore, developed is that no available gimbal technology provided the highly accurate, high speed, sub-micrometer movement in three axes that is required for such a system. Traditional gimbals use conventional electrical motors, such as direct current stepper motors, which do not have the accuracy, speed, and sub-micrometer movement required for this, and other applications, such as pin-point photography, ground position sensing, and targeting, which is needed in UAV applications. Furthermore, existing gimbals do not have the light weight, three axis range of motion, or instrument payload characteristics required for most UAV applications.
A new gimbal, which avoids the shortcomings attendant with the prior art devices and practices utilized heretofore, is the subject matter of the present application.